In brain science, there are two phenomena which are becoming increasing common in modern society. Firstly, rates of depression and anxiety disorders are increasing, with as many as one in five people either clinically depressed or anxious at any given time. Secondly, our aging population is revealing a range of cognitive problems associated with aging, including memory loss and other cognitive impairments. Each of these has a common thread - They are underpinned by clear deficits in neurochemical function. You have probably heard that "depression is caused by a serotonin imbalance"...